Previous digs in Oxyrynchus have unearthed temples dedicated to Osiris, the Egyptian god of the afterlife, but the exact nature of the latest discovery has left the experts baffled but excited.

Padró described the underground stone structure as "incredibly good, but we don't know what it is".

Over 45 tonnes of rock was moved to get at the hidden treasures, in a meticulous operation overseen by an architect and an engineer.

Once inside, the archaeologists found "five or six coats of paint on the walls, the last of which was from the Coptic period of the first Christians."

Among the plant motifs and inscriptions was something special -- the "figure of a young man, with curly hair, dressed in a short tunic and with his hand raised as if giving a blessing," according to Padró.

"We could be dealing with a very early image of Jesus Christ," he added.

The figure is under protection while a team begins to translate the inscriptions surrounding it.

Archaeological work in the area is continuing as there has still not been time to excavate another unidentified structure connected to the tombs via a set of very worn steps.